#ifndef __ZZIP_INTERNAL_MMAP_H
#define __ZZIP_INTERNAL_MMAP_H
#include <zzip_types.h>

/*
 * DO NOT USE THIS CODE.
 *
 * It is an internal header file for zziplib that carries some inline
 * functions (or just static members) and a few defines, simply to be
 * able to reuse these across - and have everything in a specific place.
 *
 * Copyright (c) 2002,2003 Guido Draheim
 *          All rights reserved,
 *          use under the restrictions of the
 *          Lesser GNU General Public License
 *          or alternatively the restrictions
 *          of the Mozilla Public License 1.1
 */

#ifdef _USE_MMAP
    #if    defined ZZIP_HAVE_SYS_MMAN_H
        #include <sys/mman.h>
        #define USE_POSIX_MMAP 1
    #elif defined ZZIP_HAVE_WINBASE_H || defined WIN32
        #include <windows.h>
        #define USE_WIN32_MMAP 1
    #else
        #undef _USE_MMAP
    #endif
#endif

/* -------------- specify MMAP function imports --------------------------- */

#if     defined  USE_POSIX_MMAP
    #define USE_MMAP 1

    #define _zzip_mmap(user, fd, offs, len) \
    mmap(0, len, PROT_READ, MAP_SHARED, fd, offs)
    #define _zzip_munmap(user, ptr, len) \
    munmap(ptr, len)
    #define _zzip_getpagesize(user) getpagesize()

    #ifndef MAP_FAILED /* hpux10.20 does not have it */
        #define MAP_FAILED ((void*)(-1))
    #endif

#elif   defined USE_WIN32_MMAP
    #define USE_MMAP 1
    #ifndef MAP_FAILED
        #define MAP_FAILED 0
    #endif
/* we (ab)use the "*user" variable to store the FileMapping handle */
/* which assumes (sizeof(long) == sizeof(HANDLE)) */

static size_t win32_getpagesize()
{
    SYSTEM_INFO si; GetSystemInfo(&si);
    return si.dwAllocationGranularity;
}
static void * win32_mmap(long* user, __zzipfd fd, zzip_off_t offs, size_t len)
{
    if (!user || *user != 1)  /* || offs % getpagesize() */
        return 0;
    {
        HANDLE hFile = (HANDLE)_get_osfhandle(fd);
        if (hFile)
            *user = (int)CreateFileMapping(hFile, 0, PAGE_READONLY, 0, 0, NULL);
        if (*user)
        {
            char* p = 0;
            p = MapViewOfFile(*(HANDLE*)user, FILE_MAP_READ, 0, offs, len);
            if (p) return p + offs;
            CloseHandle(*(HANDLE*)user); *user = 1;
        }
        return MAP_FAILED;
    }
}
static void win32_munmap(long* user, char* fd_map, size_t len)
{
    UnmapViewOfFile(fd_map);
    CloseHandle(*(HANDLE*)user); *user = 1;
}

    #define _zzip_mmap(user, fd, offs, len) \
    win32_mmap((long*)&(user), fd, offs, len)
    #define _zzip_munmap(user, ptr, len) \
    win32_munmap((long*)&(user), ptr, len)
    #define _zzip_getpagesize(user) win32_getpagesize()

#else   /* disable */
    #define USE_MMAP 0
/* USE_MAP is intentional: we expect the compiler to do some "code removal"
 * on any source code enclosed in if (USE_MMAP) {...}   i.e. the unreachable
 * branch of an if (0) {....} is not emitted to the final object binary. */

    #ifndef MAP_FAILED
        #define MAP_FAILED 0
    #endif

    #define _zzip_mmap(user, fd, offs, len) (MAP_FAILED)
    #define _zzip_munmap(user, ptr, len) {}
    #define _zzip_getpagesize(user) 1

#endif /* USE_MMAP defines */


#endif